We know that high-profile cloud platforms are big—and are only going to get bigger. But don't assume that once an organization moves part or all of its tech functions to a public cloud system, that the migration is permanent. In fact, one-quarter of companies are transferring IT services from public cloud providers to on-premise systems and/or private cloud models, according to a recent survey from CompTIA. Among the concerns about public clouds are security, costs, and reliability and performance issues. Of course, this hardly represents a complete reversal of the trend toward cloud computing. The public cloud services market will grow to $131 billion worldwide this year, compared to $111 billion in 2012, according to research from Gartner. It does indicate, however, that the public cloud hardly serves as the sole option for every organization's business strategies or for every tech need. "Once companies hit a stage where they are using cloud systems as a standard part of IT architecture, they weigh the pros and cons of various providers and models and continually shift to achieve the optimal mix," says Seth Robinson, director of technology analysis and market research for CompTIA, which is a non-profit trade education, certification and advocacy association serving the IT community. Another interesting note from the report: It appears that more medium-sized companies are embracing various cloud functions than their larger counterparts—and we've highlighted several here. More than 500 technology and business professionals took part in the research. For more about the findings, click here.